Culverts, pipes, ditches, and other drainage structures are in wide use for such reasons as preventing soil erosion and controlling runoff. Drainage structures may be installed under roadways and railroads to prevent flooding or to prevent water damage to the surrounding area. In other locations, drainage structures may be used to prevent alteration of the landscape by erosion, or shifting of the soil, for example. In some areas, controlling runoff from snowmelt is another issue that may be addressed, in part, by the use of drainage structures.
In some cases, a drainage structure may lose its function because it is clogged with debris. Drainage structures may become obstructed by soil, rocks, sand, intrusion of plant roots, snow, ice, or other debris. The location of some drainage structures may make them particularly susceptible to blockage. One way to address these problems is to place a covering or grating over the openings of the drainage structure. However, these coverings may require extensive and frequent cleaning and may still allow smaller objects such as sand, silt, and gravel to enter the drainage structure. Additionally, coverings and gratings may not prevent plant roots from clogging the drainage structure. Drainage structures can be removed and replaced periodically but this often involves disturbing existing roadways and other structures. The resultant disruption to roadway or railroad traffic is costly and causes great inconvenience to travelers.